Camshaft grinding machine



Dec. 26,1950 c. J. GREEN ETAL 2,535,130

- CAMSHAFT GRINDING MACHINE Filed Oct. 19, 1948 13 Sheets-Sheet 1 Fig. I330 5 Et seq j 2o O 26' l I +70 M z 34 f Kg 35 an E E lO I 5' InventorsCLHRE/ICE J GREEN O/vA E. HILL 9 W m. Eaton.

Htwrney Dec. 26, 1950 c. J. GREEN ETAL 2,535,130

CAMSHAFT GRINDING umcmm Filed Oct. 19, 1948 13 Sheets-Sheet2 CJggzrevztors mas/v06 ,H g- 3 Own E. HILL Dec. 26, 1950 C. J. GREEN El AL(IAMSHAFT GRINDING MACHINE Filed Oct. 19, 1948 START 36' STOP 36 STHRTCYCLE e75 STOP coumoa.

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SERIES new woma MOTOR.

l- SHUNT FIELD FIELD L055 RELAY & ISELSYN GENERATogj RECTIFIED ac FROMTHYRHTRON TUBE6 5 Mb) SELSYN SPEED CONTROL PANEL Inventors Cm/aencsJGREEN O/vn E .HILL

Dec. 26, 1950 c. J. GREEN ETAL 2,535,130

CAMSHAFT GRINDING MACHINE Filed Oct. l9. 1948 l3 Sheets-Sheet 4 @0 Ilzzz/en tors CLARENCE J GREEN O/vn E. HILL 5 M (355m Dec. 26, 1950 c. J.GREEN ET AL cwsmw GRINDING max-1m:

13 Sheets-Sheet 5 Filed Oct. 19, 1948 Inventors CLARENCE JGKEEN 01m E.HILL 3 \hWLfi-tvw g Httomeg Dec. 26, 1950 c. J. GREEN ETAL 2,535,130

CAMSHAFT GRINDING MACHINE Filed Oct. 19, 1948 l5 Sheets-Sheet '7 Fig.1?

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I A 4 fur/enters L +83 CLHRENCE JG m w La 01m E. HILL as H I 33 Dec. 26,1950 c. J. GREEN ETAL CAMSHAFT GRINDING MACHINE l3 Sheets-Sheet 8 FileaOct. 19, 1948 Inventors CLARENCE JGREE/Y 0/ VA E. HILL Httorney Dec. 26,1950 c. J. GREEN ETAL 2,535,130

CAMSHAFT GRINDING MACHINE Filed Oct. 19, 1948 13 Sheets-Sheet 10 Fig.20

18 a Inventors CLH/ZENCE JGREEN 0/ VF) E. HILL Httorneg Dec. 26, 1950 c.J. GREEN ET AL- 2,535,130

CAMSHAFT GRINDING mcumn Filed Oct. 19, 1948 15 Sheets-Sheet 1:5

(AH/Paws J GREEN Oh A 1 HILL Patented Dec. 26, 1950 CAMSHAFT GRINDINGMACHINE Clarence J. Green and Oiva E. Hill, Worcester,- asslgnors toNorton Company, Worcester, Mass., a corporation of MassachusettsApplication October 19, 1948 Serial No. 55,382

The invention relates to grinding machines, and more particularly to acamshaft grinding machine.

27 Claims. (CI. 51-72) One object of the invention is to provide asimple and thoroughly practical automatic camshaft grinding machinefor.grlnding a plurality of cams on a camshaft. A further object is toprovide a hydraulically actuated electrically controlled mechanism forproducing an automatic cycle of operation. Another object is to providea work drive mechanism automatically to produce a continuously changingwork speed during a grinding operation. Another object is to provide acontinuously diminishing. work speed during a grinding operation.

Another object is to provide an automatic control for the work drivemotor whereby rocking of the rock bar to and from an operative positionserves to start and stop the motor. Another object is to provide amanually operable control for the work drive motor. Another object is toprovide a selector control whereby either the manual or the automaticcontrols for the work drive motor may be rendered operative.Anot'her'object is to provide means for delay starting of the work motoruntil the master cam is about to engage the master cam roller.

Another object of the invention is to provide an automatic grindingwheel truing mechanism for automatically truing the grinding wheel aftereach camshaft has been ground. Another object is to provide anautomatically actuated truing feed compensator automatically to advancethe grinding wheel before each pass of the truing tool across the faceof the grinding wheel. Another object is to provide means automaticallyto advance the grinding wheel feed mechanism parts to a finish grindingposition during a truing operation. A further object is to provide meansautomatically to stop reciprocation of the grinding wheel spindle duringa truing operation. Another object is to provide electric and hydraulicinterlocks between the various mechanisms of the machine. Other objectswill be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction,combinations of elements, and arrangements of parts, as will beexemplifled in the structure to be hereinafter described, and the scopeof the application of which will be indicated in the following claims.

In the accompanying drawings, in which is shown one of various possibleembodiments of the mechanical features of this invention:

Fig. 1 is a front elevation of an automatic cam grinding machineembodying this invention;

Fig. 2 is a fragmentary cross sectional view on an enlarged scale, takenapproximately on the line 2-2 of Fig. 1 through the wheel feedingmechanism;

Fig. 3 is a hydraulic piping diagram;

Fig. 4 is an electrical diagram of the electrical controls of themachine;

Fig. 5 is a vertical transverse section, on an enlarged scale, takenapproximately on the line 55 of Fig. 1, through the rock bar showing theactuating mechanism for the rock bar and the electric switches actuatedthereby;

Fig. 6 is a fragmentary view, on an enlarged scale, of the wheel feedingmechanism;

Fig. '7 is a fragmentary front elevation, on an enlarged scale, of thetable dogs and control levers;

Fig. 8 is a fragmentary plan view of the parts shown in Fig. 7;

Fig. 9 is a fragmentary front elevation, on an enlarged scale, of thereversing lever and valve and the table indexing controls;

Fig. 10 is a vertical sectional view, taken approximately on the lineIll-40 of Figs. 7 and 9;

Fig. 11 is a longitudinal sectional view, on an enlarged scale, throughone of the control valves;

Fig. 12 is a fragmentary front elevation, on an enlarged scale, of themain control lever and associated parts;

Fig. 13 is a vertical sectional view, taken approximately on the linel3-l3 of Figs. 7 and 12;

Fig. 14 is a fragmentary front elevation, on an enlarged scale, of thecontrol apparatus for actuating the Selsyn generator for controlling thework speed;

Fig. 15 is a sectional view, taken approximately on the line l5-i5 ofFig. 14;

Fig. 16 is a fragmentary detailed view, showing the adjustment for theeccentric or cam for actuating the Selsyn generator rotor;

Fig. 17 is a fragmentary view showing the drive for the master camspindle;

Fig. 18 is a fragmentary detailed view of a portion of the master camroller indexing mechanism, showing the dog bar and star wheel;

Fig. 19 is a fragmentary plan view, on an enlarged scale, of the workhead, showing the arrangement of the master cam spindle and the followerroller and associated parts;

Fig. 20 is a fragmentary detailed view of the piston and cylinder andsprings for actuating the rock bar;

Fig. 21 is an electrical diagram of the Selsyn generator controlleddrive for the work drive motor;

Fig. 22 is a cross sectional view through the rock bar and the truingtool holder;

Fig. 23 is a hydraulic diagram of the fluid motor and control valves ofthe truing feed compensator;

Fig. 24 is a plan view, on an enlarged scale, of the truing feedcompensator unit having the top cover removed;

Fig. 25 is a front elevation, on an enlarged scale, of the truing dog;

Fig. 26 is a horizontal sectional view, taken approximately on the line26-26 of Fig. 25, showing the vertical slide construction of the dog;

Fig. 27 is a fragmentary left hand side elevation, on an enlarged scaleof the table reversing lever;

Fig. 28 is a horizontal sectional view, on an enlarged scale, throughthe feed screw clutch;

Fig. 29 is a fragmentary detail view of the spring actuated detent forpositioning the clutch actuating lever; and

Fig. 30 is an elementary electric diagram of the electronic controlunit.

An automatic cam grinding machine has been illustrated in the drawingshaving a base l which supports a longitudinally movable work table II onthe usual flat way l2 and V-way l3. The table I is arranged so that itmay be moved or traversed longitudinally by a manually operable traversemechanism including 'a hand wheel l4. This traverse mechanism issubstantially identical with that shown in the expired U. S. patent toC. H. Norton, No. 762,838 dated June 14, 1904, to which reference may behad for details of disclosure not contained herein.

The table II is arranged so that it may be traversed or indexedlongitudinally by a power operated mechanism which as illustrated maycomprise a hydraulic cylinder |6 which is fixedly supported on theunderside of the table II. The cylinder I6 contains a slidably mountedpiston I! which is connected to a double end piston rod l8. Thehydraulic control mechanism for controlling the admission to and exhaustof fluid from the cylinder l6 will be described hereinafter.

The work table serves as a support for a pivotally mounted rock bar 20which is journalled in bearings 2| and 22 fixedly mounted on the tableII. The rock bar supports a rotatably mounted master cam spindle 23having a headstock center 24 at its right hand end (Fig. 1). The rockbar 20 also supports a footstock 25 having a footstock center 26. Thecenters 24 and 26 serving to support a camshaft (no shown) having aplurality of integrally formed cams to be ground.

The base l0 also serves as a support for a transversely movable wheelslide 30 which is arranged to slide transversely on a fiat way and V-way(not shown) formed on the base 10. The wheel slide 30 supports arotatable wheel spindle 3| having a rotatable grinding wheel 32 mountedon its left hand end (Fig. 1). A motor driven mechanism is provided fordriving the spindle 3| and the grinding wheel 32 comprising an electricmotor 33 mounted on the upper face of the wheel slide 30. The motor 33is connected by means of a V-belt drive (not shown) contained within abelt guard 34.

The wheel slide 30 is arranged for a transverse feeding movement to feedthe grinding wheel 32toward and from the cam to be ground. Thismechanism may comprise a rotatable feed screw which meshes with a smallgear 43.

4 35 having a forwardly extending cylindrical portion 36 which isslidably keyed within a rotatable sleeve 31. The sleeve 31 is journalledin an anti-friction bearing 36 and the rear end of the feed screw 35 isiournalled in an anti-friction bearing 33 both of which are supported infixed relationship with the base It. A rotatable shaft 40 is slidablykeyed withinthe sleeve 31 and is rotatably journalled in bearings. Theforward end of the shaft 40 supports a gear 42 The small gear 43 isfixedly mounted relative to a large gear 44, both of which are rotatablysupported on a fixed stud 45. A manually operable feed wheel 46 isconnected to the gear 44 by means of a micrometer adjusting mechanism41. A feed stop pawl 48 is 'pivotally supported by a stud 48 which arein turn supported by a bracket 54 depending from the underside of thewheel slide 36. A rotary motion of the feed screw 35 will be transmittedthrough the nut 5| to impart a transverse feeding movement to the wheelslide 30 and the grinding wheel 32.

A secondary feeding mechanism is provided to advance the grinding wheelfor a grinding wheel truing operation. This mechanism is preferablyindependent of the manual mechanism previously described. A worm 56 isformed on the outer periphery of the nut 5|. The worm 56 meshes with aworm gear 51 mounted on the lower end of a vertically arranged rotatableshaft 58. The shaft 58 is connected at its upper end to a compensatingor secondary feeding mechanism 59 which will be more fully describedhereinafter.

An automatically operated power actuated mechanism is provided forautomatically rotating the feed screw 35 to impart an infeeding movementto the grinding wheel during a grinding operation. This mechanism ispreferably a hydraulically operated mechanism comprising a cylinder 60(Figs. 3 and 6) which contains a slidably mounted piston 6|. The piston6| is provided with rack teeth 62 which mesh with a gear 63 carried by arotatable shaft 64. The shaft 64 also supports a gear 65 which mesheswith the gear 42. When fluid under pressure is passed through a pipe 66into a cylinder chamber 61 to cause the piston 6| to move toward theright, a rotary motion will be imparted through the gearing abovedescribed to rotate the feed wheel in a counter-clockwise direction soas to feed the grinding wheel 32 toward the camshaft 2'! to be ground.During this infeeding movement, fluid within a cylinder chamber 63 mayexhaust through a pipe 69. The infeeding movement of the hand wheel 46continues until the stop abutment 50 engages the end of the stop pawl 46which determines the final infeeding position of the grinding wheel.

To facilitate setting up the feeding mechanism of the machine when a newwheel is mounted thereon, to set up for different diameter work. pieces,or to facilitate manual control of the wheel feed during a grindingoperation, it is depointed end portion 482 which is arranged to en-.

gage a spring-pressed detent 488 which serves to hold the lever 488 ineither a clutched or declutched position. Apivotally mounted bell cranklever 484 is supported on a vertical stud 488. The stud 488 is carriedby a bracket 488 mounted on the front of the machine base l8. The bellcrank lever 484 is provided with a yoked portion having a pair ofopposed screws 481 and 488 which are arranged to engage diametricallyopposite sides of the cylindrical arrow-pointed projection 482 (Fig. 28)of the arm 48I. The bell crank lever 484 is also provided with a secondyoked portion 488 which carries diametrically arranged studs 488. Thestuds 488 are arranged to engage a groove 48! formed in an enlargedsleeve 482 which is flxedly mounted on the forward end of the shaft 84.A clutch member 488 is carried to I the inner end of the shaft 84. Theclutch member 488 comprises an internal gear which is arranged to meshwith an external gear 484 of the main pitch diameter which is fixedlymounted relative to the gear 88 (Fig. 29). In the position shown in Fig.28, the clutch members 483 and 484 are engaged so that movement of thepiston II will be transmitted to the rack 82, the gear 88, the clutchparts 488484, the shaft 84, the gear 88 to rotate the gear 42 whichtransmits a rotary feeding movement to the feed screw 88 and also to thefeed wheel 48. If it is desired to declutch the piston 8i from the feedscrew 85 and the feed wheel 48, the clutch lever 488 is rocked in aclockwise direction (Fig. 28) so as to move the shaft 84 toward theright (Fig. 28) thereby disengaging the clutch member 488 from theclutch member 484. In this position of the clutch parts, the feed wheel48 may be manually rotated to rotate the feed screw 85 and therebymanually position the grinding wheel 82 as desired.

A fluid pressure system is provided for supplying fluid pressure tooperate the piston 8I and other mechanisms of the machine comprising amotor driven fluid pump 18 which draws fluid through a 'pipe 18 from areservoir 11 and passes fluid under pressure through a pipe I8 to thevarious mechanisms of the machine. A control valve 88 and a controlvalve 8| are provided to control the admission to and exhaust of fluidfrom the feed cylinder 88. The valve 88 is a shuttle type valvecomprising a movable valve member 82 having a plurality of valve pistonsformed integral therewith. The valve member 82 is arranged to be shiftedby fluid under pressure controlled by a pilot valve 88 which is actuatedby a solenoid S8. Fluid under pressure is passed through the pipe 18 tothe valve 88 and also through the pipe 18 to the solenoid actuated pilotvalve 88. In the position of the valve 83 (Fig. 3) fluid under pressureis admitted from the pilot valve '88 to an end chamber in the right handend of the valve 88 to move the valve member 82 toward the left. Aplurality of ports 84, 85, 88 and 81 are Provided to control the passageof fluid through the valve 88 in a manner to be hereinafter described.

' The valve 8| is similarly a shuttle type valve 6 comprising a slidablymounted valve member 88 the movement of which is controlled by a pilotvalve 88 actuated by a solenoid S8. Fluid under pressure is passedthrough a pipe 88 into a cylinder chamber formed at the right hand endof the valve 8| to shift the valve member 88 to its left hand endposition. The valve H is provided with a plurality of ports 8|, 82, 88and 84.

Fig. 11 shows an enlarged view of the valve II to more clearly show thedetails of construction than on the small scale illustration shown inthe diagram in Fig. 3. A compression spring 88 is provided for shiftingthe valve member 88 in a direction toward the right under certainconditions which will be hereinafter described. Except for the provisionof the spring 88. the valve 8| is identical with the valve 88..

In the position of the valves 88 and 8i as illustrated in Fig. 3. fluidunder pressure passing through the pipe 18, through the port 88 passesout through the port 88 and through a pipe 88 through a needle valve 81into a right hand end chamber 88 formed in a backlash control valve 88.The backlash control valve 88 is a piston type valve comprising a pairof spaced pistons forming a valve chamber I88. During the initialinifesding movement of the grinding wheel, fluid exhausting from thecylinder chamber 88 exhausts through the pipe 88. During this exhaust offluid from the cylinder 88 fluid under pressure is admitted through apipe I88 into a left hand end chamber I82 of the backlash valve 88 toshift the valve toward the right at a rate controlled by the needle orthrottle valve81. During this shifting movement of the valve 88, thechamber I88 allows a predetermined amount of fluid to exhaust from thepipe 88 through the valve chamber I88 and out through an exhaust pipeI88 into the reservoir 11. The speed of movement of the valve 88 ascontrolled by the throttle valve 81 governs the amount of fluidpermitted to exhaust from the pipe 88 through the valve chamber I88.This exhaust of fluid is in addition to the regular controlled exhaustof fluid from the cylinder chamber 88 and serves to provide an initialrapid movement of the piston 8i to take up backlash in the feedingmechanism. A ball check valve I84 is provided in the pipe line 88 sothat when fluid under pressure is passed through the pipe 88 it may passsubstantially unrestricted into the end chamber 88 to cause a rapidreturn movement of the valve 88 into its left hand and position.

Fluid under pressure passing through the pipe 88 also may pass through athrottle valve I88 which controls the normal rate of movement of thepiston Si in a manner to be hereinafter described. Fluid under pressurepassing through the pipe 88 may also open a ball check valve I88 andpass substantially unrestricted through a pipe I81, through a port 84 inthe valve 8|. Fluid entering through the port 84 passes through acentral aperture in the slidable valve member 88 and passes out throughthe port 8I, through a pipe I88, through the pipe 88 into the cylinderchamber 88 to cause the piston 8I to move to- .ward the left. Themovement of the piston 8i I valve chamber 81 enters a port 88 in thevalve valve member 82 toward the right so that fluid under pressurepassing through the pipe 18 will pass through pipe I 08, through theport 82 in the valve 8|, out through the port 98, through the pipe 65into the cylinder chamber 81 to cause the piston 5| to move toward theright to initiate an infeeding movement of the grinding wheel 82. Fluidunder pressure passing through the pipe I09 also passes through the pipeIOI into valve chamber I02 of the backlash valve 98 to move the valve 99toward the right at a speed controlled by the throttle valve 91. Thepassing of the valve chamber I over the port at the end of the pipe 69allows a predetermined volume of fluid to exhaust from the cylinderchamber 58 rapidly to take up the backlashing in the feeding mechanismafter which continued exhaust of fluid throughthe pipe 89 passes throughpipe I08, the port 9| of the valve 8| through a central aperture in thevalve member 80, out through a port 94, through the pipe I01, throughthe throttle valve I05, the pipe 55, the port 86 of the valve 80 and outthrough the port 81 and the pipe I08 into the reservoir 10. A ball checkvalve H0 is provided in the pipe line 89 to allow substantiallyunrestricted flow of fluid through the pipe 68 into a cylinder chamber88. It will thus be readily apparent from the foregoing disclosure thatthe infeeding movemenii of the grinding wheel is controlled by valves 80and 8|. The rate of infeeding movement being controlled by the throttlevalve I and the rate and duration of the backlash take-up beingcontrolled bythe throttle valve 91.

The left hand end of the rock bar supporting the master cam spindle 28is supported within a headstock housing H5. The master cam spindle 28supports a plurality of master cams H6. one master cam for each cam onthe camshaft to be ground. A rotatable slidably mounted master camroller H1 is supported on a rotatable shaft II8 which is in turnsupported in bearings formed in the headstock housing I I5. During agrinding operation the master cam H6 is maintained in operativeengagement with the master cam follower roller III by a yieldable meansto be hereinafter described so that as the master cam spindle 23 isrotated, the master cam II5 will rotate against the follower roller II'Iwhich will impart a controlled rocking movement to the rock bar 20 so asto generate a predetermined contour on the cam being ground.

An indexing mechanism is provided for automatically indexing the mastercam roller III longitudinally on the shaft in timed relation with thelongitudinal indexing movement of the table II to position the followerroller I I1 opposite the master cam corresponding to the cam on thecamshaft 27 to be ground. This indexing mechanism may comprise a dog barI20 which is fixedly mounted relative to the base I0. The dog bar I20 isprovided with a plurality of adjustably mounted dogs I2I which arearranged in the path of a star wheel I22 (Figs. 5 and l8).

The star wheel I22 is mounted on the end of a rotatable shaft I22 theinner end of which supports a gear I24. The gear I24 meshes with a gearI25 which is mounted on a rotatable shaft I28. The shaft I28 alsosupports a gear I21 which meshes with a rack bar I28 fixedly mounted ona yoked member I28 which engages the side faces of the master cam rollerIll. This mechanism for indexing the master cam roller III issubstantially identical with the mechanisms shown in the prior U. 8.Patent No.1,783,'755 to Trefethen and Belden dated December 2, 1930, andalso U. 8. Patent No. 2,022,178 to Belden and Silven dated November 26,1935, to which referencemay be had for details of disclosure notcontained herein. It will be readily apparent from the foregoingdisclosure that when the table I I is indexed longitudinally to positionsuccessive cams on the camshaft 21 to be around, an indexing movementwill be imparted to index the master cam roller II'I longitudinallyautomatically to position the roller II! in operative relation with thecorresponding master cam I IS.

A fluid pressure mechanism comprising a cylinder I35 anda piston I isprovided for rocking the rock bar 20 to and from an operative position.It is desirable to rock the bar 20 to an inoperative position so as toseparate the master cam IIB from the follower roller III before thetable II is indexed longitudinally. The piston I is connected to one endof a piston rod I31. A U-shaped frame I88 is clamped in a fixed positionon the piston rod I21 by means of nuts I88 (Figs. 5 and 20). An upwardlyextending arm I40 is fixedly mounted on the rock bar 20 by means ofscrews I and I 42. The upper end of the arm I40 is provided with a pairof horizontally extending arms I48 and I44. A pair of tension springsI45 and I48 are connected at one end to the opposite ends of theU-shaped frame Ill. The other ends of the springs I45 and I48 areconnected by screws I41 and I48 to the arms I48 and I44 respectively. Byadjusting the screws I41 and I48, the tension of the springs I45 and I46may be varied as desired. The arms I48 and I44 of the arm I40 areprovided with rollers I48 and I50 respectively which are arranged to beengaged by the U-shaped frame I 88 when the piston I88 is moved towardthe right (Fig. 5). When fluid under pressure is admitted through a portI5I into a cylinder chamber I52 to move the piston I85 toward the right,the U-shaped frame I38 will be moved into engagement with the rollersI49 and I50 after which continued movement of the piston I36 toward theright will swing the arm I40 in a clockwise direction to impart aclockwise movement to the rock bar 20 thereby separating the master camHi from the follower roller II1. During this movement of the piston I28,fluid is exhausted from a cylinder chamber I53 through a port I 54. Thescrews I41 and I48 are preferably adjusted so that when the piston I20is in its extreme left hand end position, the tension of the springs I45and I48 will be sufilcient to maintain the master cam [I0 in operativeengagement with the periphery of the follower roller Ill during r0-tation of the master cam spindle 28 so as to impart a controlled rockingmovement to the rock bar 20 during a cam grinding operation.

As the piston I85 moves toward the right (Fig. 20), to shift the rockbar 20 to an inoperative position, the U-shaped frame I38 moves towardthe right and due to the clearance between the frame I88 and the rollersI 48 and I50 relieves the tension on the springs I45 and I48. Duringmovement of the piston I36 and frame I38 toward the right, the frame I38engages the rollers I49and I58 and rocks the arm I48 and rock bar 28 toan inoperative position. By utilizing this construction, the extendingand contracting of the springs I45 and I46 is reduced to a minimum.During movement of the piston I36 toward the left (Fig. 20), the cam II6engages the follower roller II1 (Fig. after which the continued movementof the frame I88 toward the left separates the frame I38 from therollers I49 and I58 and increases the tension on the springs I45 and I46to the desired operating tension. The movement of the piston I36 towardthe left continued until the piston I36 engages an adjustable stop screwI36a (Fig.

When the solenoid S3 of the valve 88 is energized to shift the valvemember 82 to the right so as to pass fluid under pressure through thepipe I89 to the .valve 8|, fluid is also passed through a pipe I55,through the port I5I, into the cylinder chamber I52 to rock the rock bar28 to an inoperative position. At the same time fluid under pressure ispassed to the cylinder chamber 68 of the feed cylinder 68 so that whenthe grinding wheel is moved to a rearward or inoperative position, therock bar is also rocked to an inoperative position to separate themaster cam II6 from the follower roller H1 8. sufficient distance sothat it is unnecessary to back oil the grinding wheel beyond the feedstroke before the next table indexing movement. This separation alsoserves to facilitate loading and unloading of camshafts. Duringadmission of fluidto the cylinder chamber I52, fluid is exhausted from acylinder chamber I56 through the port I54, through a pipe I51, throughthe valve 88 and the exhaust pipe I83 into the reservoir 11.

Similarly, when the valve 88 is in the position illustrated in Fig. 3,fluid under pressure passing from the valve 88 through the pipe 96passes through the pipe I51 into the cylinder chamber I56 to move thepiston I36 toward the left (Fig.

3) to move the rock bar 28 in a counter-clockwise direction to bring themaster cam II6 into operative engagement with the follower roller II1.

A fluid pressure cylinder I68 and a piston I6I are provided forcontrolling the speed of the work driving motor so as to produce acontinuously changing work speed during a grinding operation in a mannerto be hereinafter described. The piston I6I is connected to a piston rodI62. WherLfluid under pressure is passed through the pipe I55, it passesthrough a throttle valve I63, through a second throttle valve I64 into acylinder chamber I65 to cause the piston I6I to move toward the right.During this movement of the piston I6I, fluid within a cylinder chamberI66 is exhausted through a throttle valve I61, through the pipe I51,through the valve 88 and through the pipe I83 into the reservoir 11. Aball check valve I68 is provided so that fluid exhausting from thecylinder chamber I65 may pass through the ball check valve I68 thusbypassing the throttle valve I63 so as to allow a rapid return movementof the piston I6I as it moves toward the left. It will be readilyapparent from the foregoing disclosure that move ment of the valve 88serves not only to control the passage of fluid to the feed cylinder 68but also serves to pass fluid to and from the rock bar cylinder I35 andalso to the work speed control cylinder I68.

A suitable control mechanism is provided for automatically controllingthe flow of fluid to and from the table cylinder I6 so that the tablemay be automatically indexed longitudinally. -This mechanism maycomprise a reversing lever I15 which is mounted on the upper end of avertical shaft I16. The lower end of the shaft I18 is provided with anintegrally formed rock arm I11 which is connected by means of a stud I18with a link arm I19. The other end of the link I18 is connected by astud I68 with the rotor I8I of a reversing valve I82. The reversinglever I15 is provided with a pair of projecting offset lugs I83 and I84(Figs. 10 and 2'1) which are arranged to be engaged by reversing dogsI85 and I86 respectively. As the table II moves longitudinally, one orthe other of the reversing dogs I85 or I86 will engage the lugs I83-orI84 respectively and rock the vertical shaft I16 so as to impart arotary motion to the valve rotor I8I to change the direction of flow offluid to the table cylinder. A spring actuated load and flre mechanismcomprising a spring I81 is provided for rapidly snapping the reversingvalve into its reverse position. As shown diagrammatically in Fig, 3,the reversing lever I15 is shown directly adjacent to the reversingvalve I82. Fluid under pressure from the pump passing through the pipe18 enters a chamber I88 and passes through the valve rotor to a chamberI89, through a pipe I98 into a right hand end chamber I9I of a shuttlevalve I92 to move the slidably mounted valve member I93 toward the left.During the movement of the valve member I93 toward the left, fluidwithin a left hand end chamber I94 in the valve I92 may exhaust througha pipe I95 in a manner to be hereinafter described. Fluid may pass fromthe valve I92 through a pipe I96 into a cylinder chamber I91 formed inthe left hand end of the cylinder I6 or may pass through a pipe I98 intoa cylinder chamber I99 formed at the right hand end of the cylinder I8.The shuttle type valve I92 serves as a reversing valve to change thedirection of flow of fluid through the pipes I96 and I91to change thedirection of movement of the table II. A pair of control valves 288 and28I are provided to control the admission to and exhaust of fluid fromthe shuttle valve I92. The control valves 288 and 28I are substantiallyidentical with valves 88 and BI and therefore have not been shown exceptdiagrammatically in Fig. 3. The control valve 288 comprises a shuttletype slidably mounted valve member 282 and a pilot valve 283 which isactuated by a solenoid S2. Fluid under pressure from the pump passingthrough pipe 18 enters the pilot valve 283 and passes through a passagein the valve 288 into the right hand end chamber to shift the valvemember 282 toward the left.

A small diameter pipe 18a, of approximately one eighth inch diameterconnects the pipe 18 with the pipe 2I8 which serves when the valve 288is positioned as illustrated in Fig. 3 to pass a small quantity of fluidunder pressure through both of the pipes 285 and 2I8 into the cylinderchambers I91 and I99. The quantity of fluid passing through the pipe I18being merely suflicient to compensate for leakage and thereby to preventair from getting into the system.

In the position of the valve 288 as illustrated in Fig. 3, fluid underpressure in the pipe 18 passes through the pipe 18a, through a pipe 2I6into a valve chamber and also passes through a pipe 285, through ports286 and 2 in the valve I92.

ii through port 291 and 2I2 and the pipes I98 and Ill into the cylinderchambers I91 and I99. It will be readily apparent that fluid underpressure is balanced on opposite sides of the piston II to facilitate amanual traversing movement of the table II by means of the hand traversewheel I4. It will be readily apparent from the foregoing disclosure thatfluid may readily pass from cylinder chamber I91 through the pipes,ports and valve 299 into the cylinder chamber I33 to facilitate a manualtraverse of the table I I without overcoming fluid under pressure withinthe system.

, when solenoid B2 is energized to admit fluid under pressure to thevalve chamber at the left hand end of the valve 299 to move the valvemember 292 toward the right, fluid under pressure from the pipe 18passes through the pipe 294 and out through the port 298 in the valve299, through the pipe 295 will pass through the ports 299 and 291 in thevalve I92 and through the pipe I98 into the cylinder chamber I99 tocause the table II to move toward the right.

Similarly when the shuttle valve I93 is moved toward the right into anextreme right hand end position, fluid under pressure passing throughthe pipe 295 passes through the port 296, into a valve chamber in thevalve I92, through the port 2| 2, and through the pipe I 96 into thecylinder chamber I91 to cause the cylinder I 5 and the table II to movetoward the left. It will be readily apparent from the foregoingdisclosure that when the solenoid S2 is energized, the valve 299 will bepositioned to control the admission of fluid through the pipe 295 to theshuttle valve I92 and the table cylinder I9. When the solenoid S2 isdeenergized, the valve 299 is positioned as shown in Fig. 3 tofacilitate bypassing of fluid between the opposite ends of the cylinderI6 to facilitate a manual traverse of the table II. The actuation of thereversing valve I82, as previously described, controls the shiftingmovement of the shuttle valve I92 to change the direction of movement ofthe table II.

The valve 29I comprises a slidably mounted valve member 2I5 and a pilotvalve 2I6 which is actuated by a solenoid $1. In the position of thevalve 29I as illustrated in Fig. 3 with the solenoid Bl deenergized,fluid under pressure in the pipe 13 passes through the pilot valve 2I6,through a passage in the valve 2I9 to move the valve member 2I5 towardthe left. In this position of the valve, fluid under pressure in thepipe 2I9 passes through a port 2I'I into a valve chamber within thevalve 2I9, through a port 2 I8, through a pipe 2", through a throttlevalve 229, through a pipe 22 I and through a relief valve 222 into thereservoir 11.

when the solenoid S1 is energized to shift the pilot valve 2I8 towardthe left, fluid under pressure from the pipe 18 passes through a passagein the valve 29I into the chamber at the left hand end of the valve tomove the valve member 2I5 toward the right so that fluid exhaustingthrough the pipe 2I9 from the shuttle valve I92 and the cylinder I9 maypass through the port 2", through a chamber in the valve 2!, through aport 223, through a pipe 224, through a throttle valve 225 which servesto throttle the speed of movement of the table II to a slow truing speedfor a truing operation. Fluid passing through the throttle valve 225passes through the pipe 2 I 9, the throttle valve 229, the pipe 22I andthe relief valve 222 into the reservoir 11.

When the reversing lever I I5 counterclockwise direction (Fig. 3) intoits reverse position, fluid under pressure will pass through a pipe 228,through the pipe I99 into the end chamber I 94 of the valve I92 to shiftthe valve member I93 toward the right into its reverse position so as toreverse the direction of movement of the table II.

Fluid exhausting through the pipe 224 during the normal table indexingmovement may pass through a throttle valve 229a which serves to controlthe normal indexing speed of the table II and pass through a ball checkvalve 22?, through a pipe 228, through a port 229 into a control valve239 which is actuated by a solenoid BI. As shown in Fig. 3, solenoid SIis energized and the valve member is in its extreme left hand endposition so that fluid passing through the port 229 passes out through aport 23I, through a pipe 282, through a port 233 in a control valve 234.The control valve 234 is substantially identical with control valves 89and 8| and comprises a slidably mounted valve member 235, and a pilotvalve 238 which is actuated by a solenoid $4. In the position of thevalve 234 (Fig. 3) fluid under pressure in the pipe I8 passes throughthe pilot valve, through a passage in the valve 234 into the left handend chamber to shift the valve member 235 into its extreme right handend position. Fluid under pressure entering the port 233 passes outthrough a port 231, through a pipe I95 into a chamber 238 formed at thelower end of a spring pressed valve 239. Pressure entering the valvechamber 238 raises the valve member 249 so that fluid within the pipe2I9 may exhaust through a chamber in the valve 239 and pass out througha pipe 24I, through a throttle valve 242, through a pipe 243 and throughthe relief valve 222 into the reservoir ll. The valve 239 is operativeduring the idle return stroke of the table II to facilitate a rapidreturn stroke. The valve 242 serves to regulate fluid exhaust throughthe valve 239 so that the rate of the idle stroke may be rapidlyadjusted.

The solenoid actuated valve 239 serves when solenoid SI is deenergizedto admit fluid under pressure to an index cylinder 245 to move a piston246 downwardly against the compression of a spring 244.

The index cylinder serves to control a pair of indexing plungers to behereinafter described. In order to facilitate an automatic indexing ofthe table II,. a plurality of indexing dogs 24! are adjust-ably mountedon the front edge of the machin table II. There is one dog 24'! forlocating the table in the position for grinding each cam on the camshaft21. A vertically movable plunger 248 is provided at its upper end withan arrow-pointed end portion 249 which is arranged in the path of thedogs 241. When the table moves toward the right (Fig. 3) the first dog241 engages the arrow point 249 on the plunger 249 and depresses theplunger 248 to actuate and open the normally closed limit switch LS3. Atthe same time the downward movement of the plunger 248 operates througha bell crank lever 259 (Fig. 9) to close a normally open limit switchLS9. The bell crank lever 259 is actuated by means of a transverselyarranged plunger 25I carried by a plunger 252. A cam face 253 formed onthe plunger 248 serves when the plunger 248 is moved downwardly to movethe plunger 25I toward the right (Figs. 3 and 9) to close the limitswitch LS9. When the plunger 248 is moved downwardly by means of the dog241 engaging the arrow point is shifted in a 79 249, the table movementis slowed down so that the table will stop when the right hand side faceof the dog 241 moves adjacent to or into engagement with a stop surface254 formed on the plunger 252. Aiter a cam has been ground to thedesired extent, fluid under pressure is passed through a pipe 255 fromthe valve 235 into a chamber 255 at the upper end of the index cylinder245 to move the piston 248 downwardly. The downward movement of thepiston 248 moves the plunger 252 downwardly. I'his downward movement ofthe plunger 252 serves to allow the plunger 25! to move toward the leftto open the limit switch LS and at the same time withdraw the plunger252 out of the path of the table index dog 241 so that the table I maystart its next indexing movement toward the right. As soon as theplunger 252 has passed the first dog 241, the valve 235 is actuated toallow fluid to exhaust through the pipe 255 from the cylinder chamber255 thereby releasin the compression of the spring 242 which allows theplungers 252 and 248 to move upwardly into the position shown in Fig. 3.The table indexing movement continues until the second dog engages thearrow point 241 and again stops the table II in an indexed position in amanner similar to that above described.

A wheel spindle reciprocating mechanism is provided within the wheelslide 35 for reciprocating the wheel spindle 3| axially within itsbearings during a grinding operation. The mechanism has not beenillustrated in detail since it is not considered a part of the presentinvention. Reference may be had to the prior United States patent to G.T. Muskovin dated April 8, 1941 for details of disclosure not containedherein. Briefly the valve 235 serves when the solenoid is deenergized toadmit fluid to the index cylinder 245. When solenoid SI is energized thevalve 235 serves to allow fluid to exhaust from a cylinder chamber 255in a cylinder 25i which controls the stopping and starting of the wheelspindle reciprocation. Fluid exhausting from the cylinder chamber 255passes through a pipe 252 which connects with the pipe 228. The solenoidSi is energized only when the machine is set for a truing operation orin a loading position. At all other times the wheel spindlereciprocating mechanism is operative to reciprocate the wheel axiallyduring a grinding operation. The valve 234 serves when solenoid S4 isdeenergized to admit fluid to the cylinder chamber 255 to stop the wheelspindle reciprocation. This happens only when solenoid SI is alsoenergized. When solenoid S4 is deenergized the valve 234 also passesfluid to the table index cylinder after an electric counter has countedout to again index the table II for the next grinding opera; tion. Whensolenoid S4 is deenergized and sole noid SI is energized during a truingoperation. fluid under pressure is passed through the pipe 225 to holdthe check valve 221 closed so that fluid exhausting from the tablecylinder l5 must pass through the truing speed control valve 225 toprovide a slow traversing movement of the table.

The secondary wheel feeding mechanism, namely the compensator 59 isshown diagrammatically in Fig. 3 as a cylinder 255 and a piston 255. Apipe 251 connects the pipe I95 with the compensator unit 59. A pipe 245connects the pipe I95 with the compensator unit 58. A shutratchetmechanism to rotate the vertical shaft 55 (Fig. 2) to impart a rotarymotion to the feed nut 5| so as to advance the grinding wheel 82 beforeeach pass of the truing tool across the face of the wheel. Thiscompensating adjustment of the feed nut 5i facilitates an advancingmovement of the grinding wheel without disturbing the normally operatedgrinding wheel feed mechanism.

A cycle control lever 215 is pivotally supported on the front of themachine base on a stud 211. when the cycle control lever is rocked in aclockwise direction it closes a cycle start switch 212 to start agrinding cycle. A cycle stop switch 213 is arranged so that when thelever 215 is rocked in a counter-clockwise direction, the cycle stopswitch 213 will be opened to stop the grinding cycle when desired.

A main control lever 215 (Figs. 1 and 13) is mounted on the upper end ofa vertically arranged shaft 215. The lower end of the shaft 218 isprovided with an actuating arm 211 which is arranged to engage anactuating plunger 218 which in turn serves to actuate a limit switchLS1. A compression spring 219 serves normally to hold the plunger 218 inan uppermost position. A vertically arranged plunger 285 having an arrowpoint end 28I carries an arm 282 at its lower end. The arm 282 isprovided with an adjustable screw 283 to actuate a limit switch LS9. Thearm 282 is also provided with an adjustable stop screw 284 to actuate alimit switch LSi. A spring 295 serves normally to hold the plunger 285in an uppermost position. As the table ii is moved longitudinally, a dog285 engages the arrow point on the plunger 285 to depress the plunger285 so as to actuate both the limit switch LSi and the limit switch LS9as will be more fully described hereinafter. The rotary motion of thecontrol lever 215 is restricted by means oi. a stud 289 and an arcuatenotch 288 formed in the lower surface of the control lever 215. Aprojection 352 on the control lever 215 serves during the grinding cycleto rock the lever 215 to actuate and open the normally closed limitswitch LS1 in a manner to be hereinafter described.

A suitable driving mechanism is provided for driving the master camspindle 23 and the center 24 during the rocking movement of the rock bar25 so that the camshaft being ground will be rotated at a continuouslychanging speed, such as, a speed which starts at approximately a roughgrinding speed and is continuously diminished until the work has beenground to the desired size and contour. This mechanism may comprise anelectric motor 295 mounted on the upper surface of the headstock casingH5. The motor 295 is provided with a multi V-groove pulley 29l which isconnected with V-belts 292 with a pulley 293 which is mounted on a shaft294. A small multi V-groove pulley 295 is also supported on the shaft294 and is fixedly connected to rotate with the pulley 293. MultipleV-belts 295 connect the pulley 295 with a multi V-groove pulley 291. Thepulley 291 is connected by a driving rod 295 to drive the master camspindle 23 during the rocking movement of the rock bar 25. The drivingrod 298 is pivotally connected by a stud 299 with the pulley 291. Theother end of the rod 298 is connected by a universal joint 355 with abracket 35l fastened to or fixedly mounted on the end of the master camspindle 23.

The headstock motor 29! is preferably a vari-- able speed D. C. motorwhich is controlled by a

